Depending on your needs, you might want to use a module that supports vectors and vector operations. For instance, your example would look like this with PDL:

#!/usr/bin/perl

use PDL;

my %hash = (
  one => pdl(1,2,4),
  two => pdl(5,7,9),
);

$hash{one} += pdl(7,8,11);

print $hash{$_},"\n" for keys %hash;
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